Matrix retainer



July 26, 1932.

c. s. IVORY MATRIX RETAINER Filed April 27. 1931 INVENTOR.

ATTORNEY.

Patented July 26, 1932 I 7' UNITED STATES F TE onnsrnn s. xvonx, or PHILADELPHIA, PENNSYLVANIA, Assrenon TO THE ns'rnrn or NT 1OFFICE J. W. IVORY, OF PHILADELPHIA, PENNSYLVANIA MATRIX RETAINER Application filed April 27,

In filling a cavity dentists are often compelled to use a matrix which is held tight around the tooth to present a smooth, curved wall against Which the amalgam or other filling may be packed.

In my prior Patent No. 943,353 I disclosed a matrix retainer which served this purpose but due to the springy character of the matrix and the retainer, I found that when there tainer is disengaged from the mouth, the matrix tended to fly off the ends of the retainer.

It is therefore the object of my invention to provide a matrix retainer which is an improvement on the construction disclosed and claimed in my prior patent referred to, and which will prevent the matrix from flying off the ends of the retainer when said matrix is being wedged between the tooth to be filled and the next adjacent tooth.

To the above ends my invention consists in providing the ends of the matrix retainer with specially formed spring clips which form seats for and effect positive engagement of the matrix with the ends of the retainer, but which nevertheless permits of easy and instantaneous detachment of said matrix from the end of said retainer.

My invention further consists of other various novel features of advantage and construction, all as hereinafter described and claimed in connection with the accompanying drawing, in which:

Fig. 1 is a perspective view of a matrix retainer embodying my invention.

Fig. 2 is a plan view of Fig. 1.

Fig. 3 is, on an enlarged scale, a fragmentary plan view of one of the ends of the retainer.

Fig. 4 is a view in elevation of Fig. 3.

Fig. 5 is a bottom plan view of Fig. 4:.

Fig. 6 is a perspective view showing a modified form of my invention.

Fig. 7 is a front view on an enlarged scale of the front end of the matrix retainer shown in Fig. 6.

Fig. 8 represents a side elevation of Fig. 7.

Fig. 9 is a plan view of amatrix hand.

For the purpose of illustrating my invention, I have shown in the accompanying drawing several illustrations of applications there- 1931. Serial No. 533,043.

of which are at present preferred by me, since the same have been found in practice to give satisfactory and reliable results, although it is to be understood that the various instrumentalities of which my invention consists can be variously arrangedand organized and that my invention is not limited to the precise arrangement and organization of these instrumentalities as herein shown and described. j

Referring to'the drawing in which like reference characters indicate like parts, my invention consists of the generally U-shaped sprlng member 1, the limbs 2 and 3 of which are deflected downwardly and inwardl at to form the prongs or jaws 6 and 7 which terminate in the lugs or points 9. At the junction of the limbs 2 ant 3 of the U-shaped spring member 1 is provided an enlarged portion 1O through which passes the screw 12 which carries the threaded nut 13. The screw 12 is pivoted at 14s to the toggle links 16 and 17 which, in turn, are pivoted at 20 to the ju11ction 4 of the limbs 2 and 3 with the prongs 6 and 7 to actuate said prongs against the tension of'the U-shaped spring 1.. In practice, a matrix 22 which consists of resilient sheet metal and which is provided with the holes 23, is secured to thetermina'ls of the prongs 6 and?- by engagement 'ofthe lugs 9 with the holes 23. In order to provide for adjustment I use the curved abutments 24, carried by the ends of the prongs 6 and 7 which serve to curvethe matrix to conform to the shape of the particular tooth to which it is applied.

WVhen the matrix 22 is being applied to the tooth to be filled, it is first secured to the termmals of the jaws or prongs 6 and 7 by e11- gagement of-the holes 23 in the matrix with the lugs 9. The whole device is then inserted into the patients mouth and the matrix is manipulated or manoeuvred to be inserted between the tooth to be filled and the next adjacent tooth. According to prior constructions, such as illustrated in my prior patent for instance, the matrix, being engaged only by the lugs 9, tends to fly off the terminals'of the matrix and if it doesnot fly off it tends to assume a slanting or inclined position when tightened around the tooth. I11 order to guard against the disengagement of the matrix from the lugs 9 while it is being applied to the tooth to be treated, and to insure perfeet alignment, that is, to insure that the matrix 22 will present a perfectly aligned wall at the proper point desired, I provide the spring clips 26, the bottom ends 27 of which are turned upwardly to a slight extent as illustrated in Figs. 1 and 4, said spring clips 10 being carried by the prongs 6 and 7 in proximity to the terminal lugs 9. By the provision of the spring clips 26, it is necessary, in engaging the matrix 22 with the lugs 9, to insert said matrix at a slight angle as shown in dotted lines in Fig. l so that when the matrix 22 is straightened after engagement with the lugs 9, the bottom edge of the matrix will be firmly engaged by the bottom inclined wall 27 of the spring clip 26. Thus the matrix 22 29 is not only insured against accidental disengagement by the positive disengagement afforded by the spring clip 26, but the spring clips 26 also serve to support the bottom edge of the matrix 22 to insure perfect alignment. 5 In Figs. 6, 7 and 8 I have shown a modified form of the spring clip 26, which in addition to the bottom upwardly inclined wall 27 also is provided with the upper downwardly deflected or over-hanging portion 30 which serves to engage the upper edge of the matrix. In this construction positive engagement of the matrix with the bottom 27 and top 30 of the matrix 22 is accomplished.

lVhen the dentist desires to remove the matrix from between the teeth, it can be easily disengaged from the lug 9 and the spring clips 26 bya slight manipulation of the matrix retainer, after which the matrix can be pulled out from between the packed teeth at} by hand. It is, of course, understood that the matrix 22 can be removed from the patients month without disengagement from the matrix retainer if desired.

Having thus described my invention what 5 I claim as new and desire to secure by Letters Patent, is

A matrix retainer of the character stated, comprising a U-shaped spring member having the limbs thereof formed into normally 5o separated resilient prongs, a threaded element engaging said U-shaped member, toggle connections common to the end of said threaded elements and said prongs, lugs on the ends of said prongs for engaging an apertured matrix and clips adjacent said lugs for engaging the upper and lower edges of said matrix to prevent accidental disengagement of said matrix from said lugs, each of said clips comprising a vertical wall, a down- 69 wardly deflected flange integral with the upper edge of said vertical wall and an upwardly inclined flange integral with the lower edge of said vertical wall.

In testimony whereof I aflix my signature;

CHESTER S. IVORY. 

